1. Field of the Invention
The present invention is related to a stereoscopic image display method and a stereoscopic image display apparatus for displaying stereoscopic images. The present invention is also related to a program that causes a computer to execute the stereoscopic image display method.
2. Description of the Related Art
It is known that stereoscopic viewing that utilizes parallax is enabled by combining and displaying a plurality of images. Stereoscopic images that enable stereoscopic viewing may be generated by obtaining a plurality of images of a single subject using a plurality of cameras at different positions, then combining a plurality of images utilizing the parallax of the subject included in the plurality of images.
Specifically, stereoscopic images may be generated by causing colors in the plurality of images to be different, such as red and blue, then overlapping the images. Alternatively, stereoscopic images may be generated by causing the polarization directions to be different within the plurality of images, then overlapping the images. In these cases, stereoscopic images can be viewed three dimensionally, by viewers' eyes stereoscopically viewing the stereoscopic images, which are displayed using red/blue glasses or polarizing glasses, using the automatic focusing function of the eyes (the anaglyph method and the polarizing filter method).
It is also possible to view stereoscopic images three dimensionally without using polarizing glasses and the like. The parallax barrier method and the lenticular method enable stereoscopic images to be viewed three dimensionally, by displaying the stereoscopic images on a three dimensional liquid crystal display. In these cases, the stereoscopic images are generated by cutting the plurality of images into vertically extending stripes, which are then arranged alternately. Another example of a stereoscopic display method is the time division method, in which the light beam directions of left and right images are changed by the use of image separating glasses or by attaching optical elements to liquid crystal displays, and displaying the right and left images alternately.
A technique has been proposed, in which the parallax of stereoscopic images are adjusted based on user input of amounts of parallax, to change the perceived depth when displaying such stereoscopic images (refer to Japanese Unexamined Patent Publication No. 2004-207772).
When performing photography to obtain a plurality of stereoscopic images, the angle of view, the zoom magnification, the focal point, and the positional relationship between cameras are different for each photography scene. Therefore, the perceived depth is different in each of the plurality of stereoscopic images. However, stereoscopic viewing is performed by users realizing perceived depths in their minds through visual perception. Therefore, in cases that a plurality of stereoscopic images are sequentially displayed, the perceived depths of the images will change suddenly when the display switches from one stereoscopic image to another. In three dimensional viewing, depth perception is realized by the automatic focusing function of the eyes of viewers who are viewing stereoscopic images. Therefore, viewers will become extremely fatigued if the perceived depths of images switch suddenly.
Applying the technique disclosed in Japanese Unexamined Patent Publication No. 2004-207772 to change the perceived depths of stereoscopic images may be considered. However, this technique adjusts the amounts of parallax by user input. Therefore, the operations for changing the perceived depths of stereoscopic images become burdensome, particularly in the case that a plurality of stereoscopic images are to be displayed. As a result, application of this technique is inefficient.